The 16-th BIT Campus Programming Contest

A. Gifts in box

#include "bits/stdc++.h"

using namespace std;
using i64 = long long;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int n, m, h;
    cin >> n >> m >> h;

    vector<vector<int>> a(n, vector<int>(m));
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            cin >> a[i][j];
        }
    }
    vector<vector<int>> b(h, vector<int>(m));

    for (int i = 0; i < h; i++) {
        for (int j = 0; j < m; j++) {
            for (int k = 0; k < n; k++) {
                if (a[k][j] >= i + 1) {
                    b[i][j]++;
                }
            }
        }
    }
    for (int i = 0; i < h; i++) {
        for (int j = 0; j < m; j++) {
            cout << b[i][j] << " \n"[j == m - 1];
        }
    }
    return 0;
}

B. BIT Palindrome

#include "bits/stdc++.h"

using namespace std;
using i64 = long long;

constexpr int P = 1000000007;

void solve() {
    int n;
    cin >> n;

    if (n == 1) {
        cout << "0\n";
    } else if (n == 2) {
        cout << "3\n";
    } else if (n == 3) {
        cout << "18\n";
    } else {
        cout << 6LL * (n + 1) % P << '\n';
    }
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int t;
    cin >> t;
    while (t--) {
        solve();
    }
    return 0;
}

E. Equal

#include "bits/stdc++.h"

using namespace std;
using i64 = long long;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int x, y;
    cin >> x >> y;

    if (y >= x) {
        cout << y - x << '\n';
    } else {
        if (y % 2 == x % 2) {
            cout << (x - y) / 2 << '\n';
        } else {
            cout << (x + 1 - y) / 2 + 1 << '\n';
        }
    }
    return 0;
}

G. Get off work

#include "bits/stdc++.h"

using namespace std;
using i64 = long long;

void solve() {
    int n, k;
    cin >> n >> k;
    vector<vector<int>> g(n);
    vector<int> f(n);
    for (int i = 1; i < n; i++) {
        int u, v;
        cin >> u >> v;

        u--, v--;
        g[u].push_back(v);
        g[v].push_back(u);
    }
    int ans = 0;
    function<void(int, int)> dfs = [&](int cur, int pre) {
        for (auto &nex : g[cur]) {
            if (nex != pre) {
                dfs(nex, cur);
                f[cur] += f[nex];
            }
        }
        if (cur) {
            f[cur]--;
            while (f[cur] < 0) {
                f[cur] += k;
                ans++;
            } 
        }
    };
    dfs(0, -1);
    cout << ans << '\n';
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int t;
    cin >> t;
    while (t--) {
        solve();
    }
    return 0;
}

H. Happiness Index

#include "bits/stdc++.h"

using namespace std;
using i64 = long long;

#include "ext/pb_ds/assoc_container.hpp"

template <typename Key, typename Cmp_Fn = std::less<Key>>
class Set : public __gnu_pbds::tree<Key, __gnu_pbds::null_type, Cmp_Fn,
                                __gnu_pbds::rb_tree_tag,
                                __gnu_pbds::tree_order_statistics_node_update> {};

void solve() {
    int n, k;
    cin >> n >> k;
    vector<int> a(n);
    for (int i = 0; i < n; i++) {
        cin >> a[i];
    }
    auto f = [&](int x) {
        Set<pair<i64, int>> s;
        vector<i64> sum(n + 1);
        i64 res = 0;
        for (int i = 0; i <= n; i++) {
            if (i != n) {
                sum[i + 1] = sum[i] + a[i] - x;
            }
            res += s.order_of_key({sum[i] + 1, 0});
            s.insert({sum[i], i});			
        }
        return res;
    };
    cout << f(k) - f(k + 1) << '\n';
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int t;
    cin >> t;
    while (t--) {
        solve();
    }
    return 0;
}

J. Stones

#include "bits/stdc++.h"

using namespace std;
using i64 = long long;

int sg(int x) {
    if (!x) {
        return 0;
    }
    if (x & 1) {
        return (x + 1) / 2;
    }
    return sg(x / 2 - 1);
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int n;
    cin >> n;
    vector<int> a(n);
    for (int i = 0; i < n; i++) {
        cin >> a[i];
    }
    int ans = 0;

    for (int i = 0; i < n; i++) {
        ans ^= sg(a[i]);
    }
    cout << (ans ? "Alice" : "Bob") << '\n';
    
    return 0;
}

K. ZYW with tutors

#include "bits/stdc++.h"

using namespace std;
using i64 = long long;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout << "0\n";
    return 0;
}